Folding bottom core sampler

ABSTRACT

A bottom core sampler comprises a forward elongated hollow core barrel pivotally connected to a rearward, ventral fin stabilized, elongated, weighted tubular main body having a tow cable attached thereto. The pivotal connection includes a weak link for breaking after partial penetration of the downward pivoting core barrel into the bottom permitting deeper penetration by the angular push thereon by the main body. Two valves are provided for expelling water as the bottom core sample is driven into the core barrel. Continued upward pull of the tow cable withdraws the bottom core sample laden core barrel and pivots it down and back against the main body for returning to the surface with the valves closed for retaining the bottom core sample in the core barrel.

United States Patent [191 Whitney FOLDING BOTTOM CORE SAMPLER [75] Inventor: Solon G. Whitney, Houston, Tex.

[73] Assignee: Texaco Inc., New York, NY. 221 Filed: Dec 26, 1972 [2|] Appl. No.1 317,910

[52] US. Cl 175/5, 175/20, 175/244 [51] Int. Cl EZlb 7/12, E2 lb 11/02 [58] Field of Search 175/20.5, 58, 244, 245

[56] ReterencesCited UNITED STATES PATENTS 2,488,486 11/1949 Worzel 175/5 3,429,388 *2/1969 'Nesteroff et'al... 175/245 3,561,546 2/1971 Craig 175/5 [451 Apr. 23, 1974 Primary Examiner-James A. Leppink Attorney, Agent, or FirmThomas H. Whale; C. G.

Ries

[ 5 7 ABSTRACT A bottom core sampler comprises a forward elongated hollow core barrel pivotally connected to a rearward, ventral fin stabilized, elongated, weighted tubular main body having a tow cable attached thereto. The pivotal connection includes a weak link for breaking after partial penetration of the downward pivoting core barrel into the bottom permitting deeper penetration by the angular push thereon by the main body. Two valves are provided for expelling water as the bottom core sample is driven into the core barreL.

Continued upward pull of the tow cable withdraws the bottom core sample laden corebarrel and pivots it down and back against the main body for returning to the surface with the valves closed for retaining the bottom core sample in the core barrel.

- 18 Claims,- 5 Drawing Figures PATENTED APR 2 3 I9 4 SHEET 10F 2 8 1 HII E m NN QM. ow mm N 6? g T a M I T, F 1| I NW mik mammal 231974 3805888 SHEET 2 or 2 FOLDING BOTTOM CORE SAMPLER BACKGROUND OF THE INVENTION The present bottom core samplers are inadequate for all instances for various reasons. They do not penetrate deep enough to obtain a good long sample consistently, as a typical bottom sampler disclosed in US. Pat. No. 2,488,486, due to among other reasons, water in the core barrel preventing entrance of enough sample material; or in a hollow core barrel due to some of the sample material passing completely through; due to a core sampler not being forced into the bottom hard enough because of inadequate vanes; due to the angle of the bottom sampler striking and penetrating the bottom at too shallow an angle; or due to the sample material being lost and washed out of the core barrel as it is pulled to the surface. Another typical solid material sampler particularly for underwater soil sampling is disclosed in US. Pat. No. 3,429,388.

OBJECTS OF THE INVENTION Accordingly, a primary object of this invention is to provide a bottom core sampler that will penetrate deeper by angling down as it penetrates the bottom.

Another object of this invention is to provide a bottom core sampler that will return to the surface with no loss of sample material.

Still another object of this invention is to provide a bottom core sampler formed in two, fin stabilized, pivotally interconnected, elongated tubular portions, the forward portion angling down as it penetrates the bottom and folding back against the aft portion as it returns to the surface.

A further object of this invention is to provide a folding bottom core sampler operable from a moving ship that is easy to operate, is of simple configuration, is economical to build and assemble, and is of greater efficiency for the collection of samples of such a material.

Other objects and various advantages of the disclosed bottom core sampler will be apparent from the following detailed description, together with the accompanying drawings, submitted for purposes of illustration only and not intended to define the scope of the invention, reference being had for that purpose to the subjoined claims.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings diagrammatically illustrate by way of example, not by way of limitation, one form of the invention wherein like reference numerals designate corresponding parts in the several views in which:

FIG. '1 is a schematic diagrammatic side view of the folding bottom core sampler;

FIG. 2 is a schematic top view of the sampler of FIG. 1;

.FIG. 3 is a schematic detailed exploded front view of the sampler of FIG. 1;

FIG. 4 is a schematic sectional view of the sampler at 4-4 on FIG. 3; and

FIG. 5 is a schematic plan view of the sampler at 5-5 on FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention disclosed herein, the scope of .which being defined in the appended claims is not limited in its application to the details of construction and arrangement of parts shown and described, since the invention is capable of other embodiments and of being practiced or carried out in various other ways. Also, it is to be understood that the phraseology or terminology employed here is for the purpose of description and not of limitation. Further, many modifications and variations of the invention as hereinbeforeset forth will occur to those skilled in the art. Therefore, all such modifications and variations which are within the spirit and scope of the invention herein are included and only such limitations should be imposed as are indicated in the appended claims.

SAMPLER 10 FIG. 1 discloses a bottom core sampler 10 for obtaining a sample of the sea floor while being towed from a moving ship. Sampler 10 comprises two principal parts, elongated hollow tubular main body 11 and forwardly positioned elongated hollow tubular core barrel 12, both parts being pivotally interconnected with pivot pin connection 13 connecting the lower forward end or bow of the main body 11 to the lower aft end of the core barrel 12. A weak link connection 14 having a shear pin 14a in cooperation with the pivot 13 maintains the two elongated parts substantially coaxial. Upon shearing of the shear pin 14a due to an upward, sudden force component normal to the sampler longitudinalforce component as the sampler suddenly decelerates as the core barrel strikes and is driven into the bottom, the core barrel pivots about pivotal connection 13 as it finishes burying itself in a curved path into the bottom. Continued pull on the cable 15 pivots the core barrel l2 rearwardly into juxtaposition with the main body 11, as illustrated in broken lines, FIG. 1.

MAIN BODY 11 The main body 11, FIGS. 1, 2, and 3, comprises an elongated tube 16, FIG. 1, having an upper fin 17 secured thereto, as by welding. Fin 17 extends rearwardly beyond the stern of the main body to form an additional vertical stabilizing fin 18 and it extends forwardly for increased longitudinal stabilizing effect in addition to providing a forward point for attachment of the weak connection 14.

Likewise, tow cable 15 is connected in a suitable hole in the forward upper edge of the fin 17.

Two stabilizing ventral fins 19 and 20, FIGS. 1 3, are fixed to the undersides of the elongated tube 16 at an angle of substantially 45 with a vertical plane through the longitudinal axis, particularly as seen in the end-view of FIG. 3. v

A suitable weight 21, as illustrated in the top view of FIG. 2, is secured by any suitable means as by welding internally of elongated tube 16 fillingthe front half of the tube.

,CORE BARREL 12 The core barrel 12, FIGS. land 2, which is pivoted to the fore portion of the main body 1 l by pivotal connection 13, extends coaxially and forwardly from the main body when held in position by the weak link 14. While the forward portion of core barrel 12 comprises an elongated hollow tube 22, FIG. 2, for receiving a bottom core sample as the tube is driven into the sea bottom, the rearward portion comprises a shorter aft tube section 23 substantially the same diameter as that of elongated tube 16 of the main body and slightly larger in diameter than forward core barrel hollow tube 22 for ease of being fixedly fastened thereto.

Tube section 22, FIG. 2, has depressor vanes 24 and 25 adjustably set and secured with bolt 26, FIG. 1, at a suitable negative angle of attack, and suitable mountings are provided on the lower aft end for attachment of the pivotal connection 13 to the-lower forward end or bow of the main body tube 16. A rearward swinging flapper valve closure 27, FIG. 2, is mounted on the stern of short tube 23 for closing the exit of the tube and an opening 28 and a cap 29 therefor are provided in the top of the short tube 23 with a spring 30 for urging the cap closed. Of the latter two closures 27 and 29, at least the flapper valve 27 opens to permit the water to pass through the core barrel 12 while being towed through the water. Upon a bottom sample being forced into the core barrel 12, FIGS. 1 and 3, both cap 29, FIG. 2, and the flapper valve 27 are opened by the water therein being pushed out, While both core barrel water exhausting means 27 and 29 are illustrated on the embodiment shown, obviously only one or the other may be utilized if so desired, depending on the requirements of the sampler design and the environmental conditions being encountered.

FIG. 3, an exploded front end view of the bottom sampler 10, illustrates details of depressors 24 and 25 having right-angled integral flanges 24a and 250, respectively, for adjustably attaching to flanges 31 and 32 fixed to the short aft tube 23 of core barrel 12.

FIG. 4, a view taken at 44 on FIG. 3, illustrates a typical hole pattern in right-angled flange 24a for securing the depressor vane 24 to the core barrel 12.

FIG. 5, a view taken at -5 on FIG. 4, illustrates the preferred shape of a depressor vane 24.

OPERATION With a negative angle of attack on depressor vanes 24, 25, FIGS. 1 and 2, tow cable 15 pulls bottom core sampler through the water behind a boat and diving towards the bottom at a substantial angle, such as between 30 and 45, to a plane parallel to the horizon. As the core barrel portion 22 strikes the bottom and starts to drive in, the upward force component normal to the sampler longitudinal axis of the tow cable pulling force on the sampler suddenly increases and snaps the shear pin 14a, causing the forward end of the main body 11 to tend to rise slightly and cause the weighted main body to force the core barrel portion to curve downwardly as it 'buries itself in the bottom at a much steeper angle than at the instant of contact.

As the bottom sample material is forced into the length of the core barrel 12, both flapper valve 27 and spring cap 29 open to exhaust waterfrom the core barrel. After coming to rest in the-bottom and with continual pull on the tow cable on the upper front end of the main body, the core barrel pivots rearwardly about the rising main body bow pivotal connection to the broken line position illustrated in FIG. 1, as the flapper valve 27 and spring cap close to prevent entrance of water to wash out the'bottom core sample. Vanes l7, 18, 19, and 20 then stabilize return travel of the bottom core sampler with folded core barrel to the surface.

Thus accordingly, it will be seen that the present folding bottom core sampler operates in a manner which meets each of the objects set forth hereinbefore.

While only one embodiment of the invention has been disclosed, it will beevident that various modifications are possible in the arrangement and construction of the disclosed liquid sample collecting mechanism without departing from the scope of the invention, and it is accordingly desired to comprehend within the purview of this invention such modifications as may be considered to fall within the scope of the amended claims.

I claim:

1. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises,

a. elongated body means having a longitudinal axis, said elongated body means comprising a forward facing aft portion means and a fore portion means, said aft portion means having stabilizing fin means and said fore portion means having guiding fin means,

b. means for pivotally interconnecting said two elongated body portions,

c. said fore elongated body portion means being responsive to said pivotal connecting means for deviating from said longitudinal axis for deeper penetration into the bottom for obtaining a longer and deeper bottom sample, and

d. said fore elongated body portion means being responsive to said pivotal connecting means for folding backwards against said forward facing aft elongated body portion means for being towed backwards to retain the bottom sample when being pulled back to the surface as said aft elongated body portion means is towed forwards for stabilization.

2. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises,

a. fin stabilized elongated tubular main body means having tow cable means connected to the upper forward portion thereof,

b. elongated hollow core barrel means extending forwardly substantially co-axially with said fin stabilized elongated tubular main body means,

c. means for pivotally connecting the aft end of said elongated hollow core barrel means to the fore end of said fin stabilized elongated tubular main body means,

d. said fin stabilized elongated tubular main body means being responsive to said pivotal connecting means for driving said elongated hollow core barrel means deep into the bottom for forcing a bottom sample therein, and i e. said elongated hollow core barrel means being responsive to said pivotal connecting means for being foldedback into juxtaposition with said fin stabilized elongated tubular main body means when pulled back to the surface by said vtow cable means.

3. A bottom sampler as recited in claim 2 wherein,

a. said elongated hollow-core barrel means has a valve means on the aft end thereof,

b. said elongated hollow core barrel means being responsive to said valve means for ejecting water therefrom as a bottom sample is forced therein after diving into the bottom, and

c. said elongated hollow core barrel means being responsive to said valve means for retaining the bottom sample therein as said elongated hollow core barrel means is folded back into juxtaposition with said fin stabilized elongated tubular main body means for being pulled back to the surface by said tow cable means.

means is driven into the bottom by the stabilized elongated main body means, and

c. said elongated core barrel means is responsive to said pivot pin means for being folded back against said stabilized elongated main body means with recovery movement by said tow cable means after obtaining the bottom core sample.

4. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the 10 bottom sample comprises,

a. stabilized elongated main body means having tow 10. A bottom sampler as recited in claim 9 wherein,

a. said elongated core barrel means comprises an elongated tube with a flapper valve mounted on the aft end thereof so that water is forced out of the aft cable means for towing thereof,

b. said tow cable means generating a longitudinal force component and an upward normal force component on said stabilized elongated main body means,

c. elongated core barrel means, d. means for pivotally connecting said elongated core barrel means to said stabilized elongated main body means, and

e. said stabilized elongated main body means being responsive to said tow cable means generated normal force component and said pivotal connecting ter for diving into the bottom for taking a bottom core sample and for being pulled back to the surface for recovery of the bottom core sample comprises,

means for driving said elongated core barrel means in a curved path deep into the bottom for obtaining a long bottom core sample.

5. A bottom sampler as recited in claim 4 wherein,

a. said tow cable means is responsive to said pivotally connecting means for folding said elongated core barrel means back against said stabilized elongated main body means when being pulled back to the surface for towing said elongated core barrel means backwards to retain the bottom core sample as the stabilized elongated main body means is towed forwardly.

6. A bottom sampler as recited in claim 4 wherein,

a. said stabilized main body means comprises an elongated body having two ventral stabilizing fins extending downwardly from the body and extending away from each other.

7. A bottom sampler as recited in claim 4 wherein,

a. said stabilized elongated main body means comprising a hollow tubular structure,

b. two ventral stabilizing fins extending downwardly from said elongated hollow tubular body and angled away from each other, and

c. weight means filling a substantial portion of the forward part of said elongated hollow tubular body.

said pivotally connecting means comprises,

a. pivot pin means for connecting an aft lower edge of said elongated core barrel means to a forward lower edge of said stabilized elongated main body means,

b. weak link means connecting an aft upper edge of said elongated core barrel means to a forward upper edge of said stabilized elongated main body means for breaking as the elongated core barrel a. elongated main body means having stabilizer fin means,

b. elongated core barrel means for said elongated main body means having depressor vane means set at a negative angle of attack, and

c. means for interconnecting. said two elongated means.

12. A bottom sampler as recited in claim 1 1 wherein,

a. said elongated main body means has two ventral stabilizing fins extending downwardly from the body and extending away from each other.

13. A bottom sampler as recited in claim 11 wherein,

a. said elongated main body means comprises a hollow tubular elongated body,

b. two ventral stabilizing fins extending downwardly from said hollow tubular elongated body and angled away from each other, and

c. weight means filling a substantial portion of the forward part of said hollow tubular elongated body.

14. A bottom sampler as recited in claim 11 wherein,

a. said elongated core barrel means comprises an elongated tube with a flapper valve mounted on the aft end thereof so that water is forced out of the aft end as a bottom sample is forced in the forward end of said elongated core barrel means, and

b. said flapper valve is closed to retain the bottom sample in said elongated core barrel means when pulled rearwardly from the bottom.

15. A bottom sampler as recited in claim 1 1 wherein,

a. said elongated core barrel means comprising an elongated tube with a spring valve mounted therein so that water is forced out of said elongated tube as a bottoin sample is forced in the forward end of said elongated core barrel means, and

b. said spring valve is closed to retain the bottom sample in said elongated core barrel means when pulled rearwardly from the bottom.

16. A bottom sampler as recited in claim 11 wherein said interconnecting means comprises,

a. pivot pin means for connecting an aft lower edge of said elongated core barrel means to a fore lower edge of said elongated main body means.

17. A bottom sampler as recited in claim 11 wherein said interconnecting means comprises,

a. pivot pin means for connecting an aft lower edge of said elongated core barrel means to a forward lower edge of said elongated main body means,

b. weak link means connecting an aft upper edge of said elongated core barrel means to a forward upper edge of said elongated main body means for breaking as the elongated core barrel means is driven into the bottom by the elongated main body means, and

c. said elongated core barrel means being responsive to said pivot pin means for being folded down and back against said elongated main body means with the aft end of said elongated core barrel means facing forwardly with forward movement of said elongated main body means to the surface.

18. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises,

a. stabilized elongated main body means having tow cable means for towing thereof through the water into the bottom and recovery therefrom,

b. elongated core barrel means extending forwardly of said stabilized elongated main body means,

pivot means pivotally connecting said elongated core barrel means to said stabilized elongated main bodymeans, i

d. said stabilized elongated main body means being responsive to said pivot means for driving said elongated core barrel means deeper into the bottom when contact is made therewith for obtaining a bottom sample, and

e. said elongated core barrel means is responsive to said pivot means for being folded backwards against said stabilized elongated main body means for being pulled backwards with recovery movement by said tow cable means after obtaining the bottom core sample. 

1. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises, a. elongated body means having a longitudinal axis, said elongated body means comprising a forward facing aft portion means and a fore portion means, said aft portion means having stabilizing fin means and said fore portion means having guiding fin means, b. means for pivotally interconnecting said two elongated body portions, c. said fore elongated body portion means being responsive to said pivotal connecting means for deviating from said longitudinal axis for deeper penetration into the bottom for obtaining a longer and deeper bottom sample, and d. said fore elongated body portion means being responsive to said pivotal connecting means for folding backwards against said forward facing aft elongated body portion means for being towed backwards to retain the bottom sample when being pulled back to the surface as said aft elongated body portion means is towed forwards for stabilization.
 2. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises, a. fin stabilized elongated tubular main body means having tow cable means connected to the upper forward portion thereof, b. elongated hollow core barrel means extending forwardly substantially co-axially with said fin stabilized elongated tubular main body means, c. means for pivotally connecting the aft end of said elongated hollow core barrel means to the fore end of said fin stabilized elongated tubular main body means, d. said fin stabilized elongated tubular main body means being responsive to said pivotal connecting means for driving said elongated hollow core barrel means deep into the bottom for forcing a bottom sample therein, and e. said elongated hollow core barrel means being responsive to said pivotal connecting means for being folded back into juxtaposition with said fin stabilized elongated tubular main body means when pulled back to the surface by said tow cable means.
 3. A bottom sampler as recited in claim 2 wherein, a. said elongated hollow core barrel means has a valve means on the aft end thereof, b. said elongated hollow core barrel means being responsive to said valve means for ejecting water therefrom as a bottom sample is forced therein after diving into the bottom, and c. said elongated hollow core barrel means being responsive to said valve means for retaining the bottom sample therein as said elongated hollow core barrel means is folded back into juxtaposition with said fin stabilized elongated tubular main body means for being pulled back to the surface by said tow cable means.
 4. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises, a. stabilized elongated main body means having tow cable means for towing thereof, b. said tow cable means generating a longitudinal force component and an upward normal force component on said stabilized elongated main body means, c. elongated core barrel means, d. means for pivotally connecting said elongated core barrel means to said stabilized elongated main body means, and e. said stabilized elongated main body means being responsive to said tow cable means generated normal force component and said pivotal connecting means for driving said elongated core barrel means in a curved path deep into the bottom for obtaining a long bottom core sample.
 5. A bottom sampler as recited in claim 4 wherein, a. said tow cable means is responsive to said pivotally connecting means for folding said elongated core barrel means back against said stabilized elongated main body means when being pulled back to the surface for towing said elongated core barrel means backwards to retain the bottom core sample as the stabilized elongated main body means is towed forwardly.
 6. A bottom sampler as recited in claim 4 wherein, a. said stabilized main body means comprises an elongated body having two ventral stabilizing fins extending downwardly from the body and extending away from each other.
 7. A bottom sampler as recited in claim 4 wherein, a. said stabilized elongated main body means comprising a hollow tubular structure, b. two ventral stabilizing fins extending downwardly from said elongated hollow tubular body and angled away from each other, and c. weight means filling a subsTantial portion of the forward part of said elongated hollow tubular body.
 8. A bottom sampler as recited in claim 4 wherein, a. said tow cable means comprises a tow cable connected to an upper forward edge portion of said stabilized elongated main body means transversely opposite to said pivotally connecting means for generating said upward normal component of force on said stabilized elongated main body means.
 9. A bottom sampler as recited in claim 4 wherein said pivotally connecting means comprises, a. pivot pin means for connecting an aft lower edge of said elongated core barrel means to a forward lower edge of said stabilized elongated main body means, b. weak link means connecting an aft upper edge of said elongated core barrel means to a forward upper edge of said stabilized elongated main body means for breaking as the elongated core barrel means is driven into the bottom by the stabilized elongated main body means, and c. said elongated core barrel means is responsive to said pivot pin means for being folded back against said stabilized elongated main body means with recovery movement by said tow cable means after obtaining the bottom core sample.
 10. A bottom sampler as recited in claim 9 wherein, a. said elongated core barrel means comprises an elongated tube with a flapper valve mounted on the aft end thereof so that water is forced out of the aft end as a bottom sample is forced in the bow of said elongated core barrel means, and b. said elongated core barrel means being responsive to said pivot pin means for being folded down and back against said stabilized elongated main body means with the stern of said elongated core barrel means facing forwardly with forward movement of said stabilized elongated main body means when being pulled back to the surface by said tow cable means for recovery of the bottom sample.
 11. A bottom core sampler for being towed underwater for diving into the bottom for taking a bottom core sample and for being pulled back to the surface for recovery of the bottom core sample comprises, a. elongated main body means having stabilizer fin means, b. elongated core barrel means for said elongated main body means having depressor vane means set at a negative angle of attack, and c. means for interconnecting said two elongated means.
 12. A bottom sampler as recited in claim 11 wherein, a. said elongated main body means has two ventral stabilizing fins extending downwardly from the body and extending away from each other.
 13. A bottom sampler as recited in claim 11 wherein, a. said elongated main body means comprises a hollow tubular elongated body, b. two ventral stabilizing fins extending downwardly from said hollow tubular elongated body and angled away from each other, and c. weight means filling a substantial portion of the forward part of said hollow tubular elongated body.
 14. A bottom sampler as recited in claim 11 wherein, a. said elongated core barrel means comprises an elongated tube with a flapper valve mounted on the aft end thereof so that water is forced out of the aft end as a bottom sample is forced in the forward end of said elongated core barrel means, and b. said flapper valve is closed to retain the bottom sample in said elongated core barrel means when pulled rearwardly from the bottom.
 15. A bottom sampler as recited in claim 11 wherein, a. said elongated core barrel means comprising an elongated tube with a spring valve mounted therein so that water is forced out of said elongated tube as a bottom sample is forced in the forward end of said elongated core barrel means, and b. said spring valve is closed to retain the bottom sample in said elongated core barrel means when pulled rearwardly from the bottom.
 16. A bottom sampler as recited in claim 11 wherein said interconnecting means comprises, a. pivot pin means for connecting an aft lower edge of said elongated core barrel means to a fore lOwer edge of said elongated main body means.
 17. A bottom sampler as recited in claim 11 wherein said interconnecting means comprises, a. pivot pin means for connecting an aft lower edge of said elongated core barrel means to a forward lower edge of said elongated main body means, b. weak link means connecting an aft upper edge of said elongated core barrel means to a forward upper edge of said elongated main body means for breaking as the elongated core barrel means is driven into the bottom by the elongated main body means, and c. said elongated core barrel means being responsive to said pivot pin means for being folded down and back against said elongated main body means with the aft end of said elongated core barrel means facing forwardly with forward movement of said elongated main body means to the surface.
 18. A bottom sampler for being towed underwater for diving into the bottom for taking a bottom sample and for being pulled back to the surface for recovery of the bottom sample comprises, a. stabilized elongated main body means having tow cable means for towing thereof through the water into the bottom and recovery therefrom, b. elongated core barrel means extending forwardly of said stabilized elongated main body means, pivot means pivotally connecting said elongated core barrel means to said stabilized elongated main body means, d. said stabilized elongated main body means being responsive to said pivot means for driving said elongated core barrel means deeper into the bottom when contact is made therewith for obtaining a bottom sample, and e. said elongated core barrel means is responsive to said pivot means for being folded backwards against said stabilized elongated main body means for being pulled backwards with recovery movement by said tow cable means after obtaining the bottom core sample. 